One problem associated with in-roadway warning light signal heads results from the requisite internal air gap needed to keep the light pattern in the desired direction. Moisture in this air gap can cause condensation to form on the inside of the lens or window of the signal head. While this condensation is often merely an aesthetic problem, it can also potentially affect the LEDs and associated electronics in the signal head, and may decrease confidence in the product from the purchasers standpoint.
U.S. Pat. No. 6,384,742 to Harrison discloses a traffic warning system which alerts approaching vehicle traffic to the presence of a pedestrian in a crosswalk. The system includes a plurality of surface mounted lights partially embedded in and placed across a roadway. The lights are activated by the pedestrian, either by manual switch or by a sensor, before he enters the crosswalk. Once activated, the flashing lights warn drivers of approaching vehicles that a pedestrian may have entered the crosswalk, and that caution should be exercised.
U.S. Pat. No. 6,597,293 to Harrison describes a traffic warning system which alerts approaching vehicle traffic to an intersection stop requirement. The system includes a plurality of above-pavement, surface mounted lights, installed in a fashion similar to currently used road reflectors, and which are partially embedded in a roadway and placed across the roadway, e.g., adjacent to and parallel with the existing stripes or stop bars designating an intersection, and constructed so that they are impervious to vehicle traffic over them. Once activated, the lights flash in the direction of oncoming traffic, and emanate directly from the roadway, to warn drivers of approaching vehicles that a stop may be required at the intersection, and that caution should be exercised.
U.S. Pat. No. 6,683,540 to Harrison teaches a traffic warning system which alerts approaching vehicle traffic to the approach of a train in a crossing. The system includes a plurality of surface mounted lights partially embedded in and placed across a roadway. Once activated, the flashing lights warn drivers of approaching vehicles that a train is approaching, and that caution should be exercised.
The foregoing patents reflect the current state of the art of which the present inventor is aware. Reference to, and discussion of, these patents is intended to aid in discharging Applicant's acknowledged duty of candor in disclosing information that may be relevant to the examination of claims to the present invention. However, it is respectfully submitted that none of the above-indicated patents disclose, teach, suggest, show, or otherwise render obvious, either singly or when considered in combination, the invention described and claimed herein.